Delayed Sequence Intubation

A strategy of time separation between the administration of a dissociative induction agent and the neuromuscular blocker to allow preintubation optimization.


INTRODUCTION



Delayed sequence intubation (DSI) differs from rapid sequence intubation (RSI), in that it separates the induction and paralysis to allow preintubation procedures such as preoxygenation in patients who are noncompliant (e.g. delirious) (FIGURE 3.1). It can be thought of as procedural sedation where the procedure is preoxygenation. In indicated situations requiring further preoxygenation, DSI is an alternative to precipitous intubation without full paralytic effect or bag-mask ventilation in the sedated and paralyzed patient. Respectively, these two traditional options increase the risk of first-pass failure or the risk of gastric insufflation and passive regurgitation in sick, nonfasted patients. Both options ensure an abbreviated period before critical levels of hypoxemia.


CLASSIC INDICATIONS



imagesPreoxygenation prior to intubation in a delirious or otherwise uncooperative hypoxemic and/or hypercapnic patient


imagesAdequate oxygenation but need for further denitrogenation of the lungs and bloodstream in order to prolong the safe apnea period in a delirious or otherwise uncooperative patient


EXTENDED INDICATIONS



imagesNeed for an additional procedure or further optimization of physiologic parameters prior to intubation in a delirious or otherwise uncooperative patient


   imagesNasogastric tube placement for a patient with upper gastrointestinal bleed and stomach filled with blood


   imagesNeed to optimize patient’s blood pressure secondary to hypotension


   imagesNeed to optimize patient’s respiratory and metabolic status secondary to metabolic acidosis



images


FIGURE 3.1 Delayed sequence intubation algorithm.


CONTRAINDICATIONS



imagesNeed for a “crash” airway


   imagesPatient unable to breathe spontaneously


   imagesPatient unable to protect his/her own airway


imagesRelative contraindications—situations in which ketamine would be less than favorable and absence of alternative agents e.g.dexmedetomidate or droperidol


   imagesElderly patients with coronary artery disease


   imagesPatients with elevated blood pressure or tachycardia


EQUIPMENT



imagesEquipment for preoxygenation


   imagesNasal cannula (NC)


   imagesNonrebreather (NRB) mask


   imagesConsider methods for positive-pressure ventilation if the patient is exhibiting physiologic shunt


      imagesVentilator and noninvasive ventilation (NIV) mask


      imagesBag-valve mask (BVM) with adjustable positive end-expiratory pressure (PEEP) valve


imagesInduction medication that maintains ventilatory drive and airway reflexes


   imagesThat is ketamine (1–2 mg/kg) given over approximately 30 seconds


imagesStandard equipment and medications for airway management


STANDARD TECHNIQUE



imagesAdministration of induction agents that do not blunt spontaneous ventilations or airway reflexes


   imagesGive a dissociative dose of ketamine (1–2 mg/kg) over approximately 30 seconds


   imagesAlternative agents


      imagesDexmedetomidine 1 μg/kg over 10 minutes


      imagesDroperidol 5 to 10 mg


        imagesAfter intubation, check electrocardiogram (ECG) to determine whether any QT prolongation


        imagesFor these two latter agents, a separate induction agent should be administered just prior to neuromuscular blocker administration


imagesPreoxygenation and denitrogenation in standard manner with oxygen saturation >95% for 2 to 3 minutes or at least eight vital capacity (VC) breaths (note: patients who have received a DSI agent cannot take VC breaths)


   imagesNRB


   imagesAlternatives in patient exhibiting shunt physiology (saturation not improving with increased FIO2)


      imagesBVM with PEEP valve


      imagesNIV—PEEP/Continuous positive airway pressure (CPAP)


      imagesPEEP levels between 5 and 15 cm H2O


      imagesFollow with apneic oxygenation


imagesConcurrent preparation for definitive airway management in standard manner


EXAMPLE OF PROCEDURE



imagesDelirious hypoxic patient not tolerating an NRB for preoxygenation


imagesKetamine 1 to 2 mg/kg by slow intravenous push


imagesPreoxygenation and denitrogenation with NRB/NC or NIPPV (Non-Invasive Positive Pressure Ventilation) for 2 to 3 minutes


imagesAdminister NMB (Neuromuscular blockade)


images45 to 60 seconds of apnea with apneic oxygenation


imagesIntubate


COMPLICATIONS



Complications from DSI are no different from complications inherent in attempts to intubate hypoxic/hypercapnic, delirious and/or otherwise unstable patients, with the exception being the establishment of a prolonged safe apnea period:


imagesAspiration


imagesGastric distention


imagesEmesis with ketamine—occurs after emergence and is a concern if the patient is allowed to emerge from the dissociated state prior to endotracheal intubation


SAFETY/QUALITY TIPS




imagesProcedural


   imagesAdministering ketamine as a quick bolus will often cause 15 to 30 seconds of apnea; this can be avoided by pushing ketamine more slowly (over 30 seconds)


   imagesApplication of a NC at high flow, in addition to either a face mask or NIV oxygenation, will optimize oxygenation and facilitate apneic oxygenation after the paralytic is given


   imagesAvoid very high positive pressure (>15 cm H20) when using NIV


imagesCognitive


   imagesThe intubating provider should be at bedside during the entire DSI procedure, prepared to abort DSI at any point and commence with RSI (by giving the paralytic)


   imagesAlthough the goal of DSI is to optimize intubating conditions, in some cases, the underlying insult can be adequately addressed during the dissociated period, and intubation avoided. We recommend that a full intubation setup be prepared for every DSI case, however.


   imagesCurrent alternatives to ketamine are inferior to ketamine for facilitating DSI; be cautious if using any other agent

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Aug 9, 2016 | Posted by in EMERGENCY MEDICINE | Comments Off on Delayed Sequence Intubation

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